The support bracket frame wiper blades that have been in long, widespread use in wiping systems for motor vehicle windshields (German Patent DE-PS 15 05 397) have a great structural height, which under the flow conditions prevailing in front of the vehicle window, especially at a high travel speed, enhance the tendency of the wiper blade to lift away. At the least, this lessens the prescribed contact pressure of the wiper blade on the window so much that the wiping quality suffers as a result.
The invention is based on a very shallow wiper blade. In a known wiper blade of this type (German Patent Disclosure DE 19 72 98 65.6 A1), one hinge pin of nonround cross section is disposed on each of the two long sides of the coupling part, and the two hinge pins have a common hinge axis. The hinge half toward the wiper blade that is thus formed cooperates with bearing bores on the wiper arm that form the hinge half of the wiper arm; the bearing bores are each open at the periphery via an introduction channel, and the channel width is adapted to the smaller pin diameter. The design of the hinge is such that during wiper operation, the hinge pins cannot move out of their bearing bores. If the wiper blade is to be removed from the wiper arm, for instance if a worn wiper blade is to be replaced by a new one, then first the wiper arm has to be folded out of the way of the window or glass, so that the wiper blade can be put into its mounting, position, In which the hinge pin can be passed through the insertion channels and the wiper blade can be separated from the arm. If this is done improperly, however, the wiper blade can on route by itself in the hinge even while the arm is being folded out of the way, and thus the blade can separate from the wiper arm unintentionally and drop onto the vehicle body and cause damage there.
In the wiper blade according to the invention, it is possible to equip the wiper arm with a pin of round cross section, which can be introduced into the bearing recess in the direction of the hinge axis. The result is a coupling and hinge system in which the hinge bolt of the wiper arm is completely surrounded by the bearing recess of the wiper blade. The release of the wiper blade from the wiper arm is accomplished by pulling the wiper blade off the bearing bolt of the wiper arm in the direction of the hinge axis, any securing means that may be present must have been released beforehand. The embodiment of the hinge half toward the wiper blade and of the coupling means is especially advantageously employed in wiping systems in which the wiper arm blade and of the coupling means is especially advantageously employed in wiping systems in which the wiper arm and the wiper blade are disposed one behind the other in terms of the wiping direction. The embodiment of the wiper blade In the region of the coupling part is especially economical, which is significant in terms of the pricing of replacement wiper blades. Besides its function as a coupling means and as a hinge half, the opportunity also exists of using the bearing recess as an excellent positioning aid, when the wiper blade is passing through mounting or test systems during its production. For smooth wiper operation, it is of essential significance that the wiper arm coupling part has two cheek regions, extending in the longitudinal direction of the wiper blade and disposed upright relative to the window or glass, by each of which one cheek region is formed on one of the two long sides of the coupling part, and furthermore the spacing between the two cheek regions is between 16 NM and 25 NM. If guide or fitting faces that are defined once and for all result, against which counterpart faces of the wiper arm can be placed cleanly during wiping operation, so that a good outcome of wiping is assured. Because of the spacing range, measured in the wiping direction, of 16 mm to 25 mm, at the greatest dimension a minimization of any tilting motion of the wiper blade about its longitudinal axis is achieved when the wiper blade reverses Its wiping direction, which if the play is great can also be associated with a certain undesired noise production. On the other hand, the width of the wiper blade measured in the wiping direction must be not exceed a certain size, for styling reasons.
In practice it has been found that these problems are solved especially well if the spacing between the two cheek regions is between 20 mm and 23 mm.
For a special binding situation, a spacing of 22 mm, measured in the wiping direction, between the two cheek regions has proved extraordinarily favorable.
Especially for reasons of appearance, it is especially advantageous if the ratio between the length of the wiper blade and the spacing between the cheek regions is between the values of 1:22 and 1:33.
In a continuation of the concept of the invention, in terms of the longitudinal direction of the wiper blade, the bearing recess is disposed near one end of the coupling part, and the thickness of the coupling part between the one end region provided with the bearing recess and the other end of the coupling part is less, at least over a longitudinal portion, than the end portion of the coupling part that has the bearing recess. The thicker end of the coupling part that has the bearing recess assures the requisite stability in the region where the force is transmitted from the wiper arm to the wiper blade.
To secure the wiper blade against unintended release from the wiper arm even in a position folded away from the window or glass, measured in the longitudinal direction of the wiper blade, the spacing from the transverse bore via the transverse groove to one end of the wiper blade is greater than to the other end of the wiper blade.
If the longitudinal portion of the coupling part that has the lesser thickness is formed by a transverse groove in the coupling part that is open toward the side of the coupling part remote from the support element. This longitudinal portion can be used as a transitional channel for securing means of the wiper arm, which are operative, when the wiper blade is disposed next to the wiper arm in the wiping direction, on the side of the wiper blade remote from the wiper arm, yet without unfavorably affecting the low structural height of the wiper blade.
It has proved to be especially advantageous if one of the two cheek regions surrounds the orifice of the bearing recess, and that the other cheek region is disposed on the portion of the coupling part that has a lesser thickness than the end region of the coupling part that is provided with the bearing recess. The result, seen in the longitudinal direction of the wiper blade, is accordingly a spacing between the two fitting faces that has proved especially advantageous in terms of wiper blade guidance during wiping operation.
If the bearing recess is embodied as a blind bore, then soiling of this bearing point, which suffers high stress, can be reduced considerably.
If the aforementioned securing means of the wiper blade are adapted to the selected width of the groove of 8 mm to 10 mm, preferably 9 mm, the result for the wiper blade during wiping operation is a further improvement in stability as well as relief of the bearing point, when the securing means are braced on the groove walls that face one another.
In order for a spoiler surface, to be disposed on the wiper blade, to be continued in the region of the coupling part as well, at least one of the two long sides of the coupling part is provided with a chamfer over one portion. If both long sides of the coupling part are provided with a chamfer of this kind, then furthermore a simplification for mounting the wiper blade on the wiper arm can also be attained.
Advantages with regard to production costs for the wiper blade are obtained if the coupling part is made from a plastic.
It can be advantageous the bearing recess in the coupling part by the bore of a guide bush seated in the coupling part, a favorable combination of sliding partners with the material for the hinge bolt can be attained.